That sounds like Barkmann's Corner. Lot's of information about that fight on the internet.
http://www.wehrmacht-awards.com/forums/showthread.php?t=157528&highlight=barkmann
There are some issues with that fight though....
The "tank" unit that Barkmann "delayed" was Troop A, 4th Cavalry Squadron (Mecz), reinforced by one platoon of E Troop (two M8 HMC) and one platoon of F Company (five M5 Light Tanks), reinforced by Battery B, 391st Field Artillery (correction: that should have been six M7 GMC). The troop was screening the flank of the southward advance by the 1st ID and CCB, 3rd AD on Marigny and southwest to Coutances and wasn't very interested in advancing due west. There was no record of air support being available and none was called for so if Barkmann was attacked by aircraft it was by accident.
1st Platoon lost four "vehicles" including two tanks and 3rd Platoon lost all its 1/4-ton GP. So Barkmann's score was actually two M5 Light Tanks, two M8 AC or GP, and six GP; ten vehicles in total. At least he got the numbers close to correct.
By that evening Marigny had fallen and the advance by the 1st ID and CCB continued west along the Coutances-Marigny Road with little interference, well south of La Lorey, turning north in the afternoon and seizing Comprond, well behind Barkmann. I'm not sure I could characterize his actions as a delay, let alone as significant, since A Troop accomplished its mission successfully.
Followed up by this:
The only possible units with Shermans that can be considered are the 745th Tank Battalion, which reported no tanks of any kind lost or damaged on 27 July and that reported only one write-off for the month, or CCB, 3rd AD.
Supposedly Barkmann was north of the N172 on the dirt road from Le Neufbourg to Le Lorey, but CCB motored down the N172 after bypassing Marigny to the west starting at late morning, advanced without significant opposition about four miles and then turned north and seized Camprond and Hill 177 at 1540.
I have found no record of major losses to the division. They reported 104 M4 Medium Tanks and 9 M5 Light Tanks damaged and lost 2-23 July. The number written off is difficult to be certain, Steve Zaloga gives 40 M4 Mediums lost for July, while the divisional Ordnance Maintenance Battalion gave 52 tanks of all types written off for the month...including apparently some lost in their initial action on 30 June. But total tanks reported operational at 2200 on 27 July were 399, exactly the same as there were at 2200 on 23 July. At 2200 hours 30 July, when the next report was made, there were 393. The 32nd Armor didn't report significant tank losses, although the 33rd had at least two M4 Mediums knocked out...at Quibou.
Nor were there excessive personnel casualties reported on that day, just 91 for the 3rd AD and 93 for the 1st ID.
There simply aren't any other units that reported significant opposition near where Barkmann supposedly was on that day. The only other candidates are B Troop and the 16th RCT, but they were along the D53 attacking south southwest from northwest of Marigny when they encountered resistance. The actions of 3rd/16th Infantry could fit, except that they were just 1/2 mile west of Marigny, had no tanks, and just one company of TDs, none of whoch were lost, when they were counterattacked by an estimated 100 Germans supported by a single tank. Possibly Barkmann, but not alone, and no armored vehicles at all lost.
Questions about the fight were:
1) Are CCA completely out of the picture?
2) Confirm that 4th AD did not stray into the area.
3) Explain the make up of 'B Troop' and the '16th RCT'.
4) Are you saying 3rd AD lost no tanks between 23rd July and 22:00 hours on 27 July?
And then the final analysis here:
1) CCA attacked south southeast, away from Marigny and Barkmann's supposed position.
2) 4th AD wasn't committed until 28 July, moving from Periers to Coutances, and was nowhere near the putative scene of this action.
3) B Troop was a Cavalry Reconnaissance Troop (Mech) comprised of three platoons of M8 AC and 1/4-ton GP. It was also reinforced by a platoon of light tanks and a platoon of assault guns. CT 16 comprised the 16th Infantry, 7th FA, B Battery, 103rd AA, A Company, 1st Med, A Company, 1st Engineers, detachment, 1st Signal Company, Reconnaissance and A Company, 634th TD Bn (SP), A Company, 635th TD Bn (towed), and A and B Company, 87th Chemical Mortar Bn.
4) No, but it is unlikely they had any write-offs, and I can find no accounts of any major losses occuring. That a battery of the 391st FA, which was attached in direct support to CCB, fired in support of A Troop, 4th Cavalry, is rather indicative that the most serious fighting was to the flank. There are also accounts of some of the cannoneers taking up small arms to help repel the German infantry assault and of the crew of an SP AA mount, probably apocryphally, "blowing the wheel off a German "Panther tank" with a hand-set charge of TNT. Frankly, I give that last story about equal weight in terms of absolute accuracy as i do Barkmann's.
Mind you, that doesn't mean that I disbelieve Barkmann, rather I disbelieve the exact accuracy of his account and suspect that in fact he was engaged heavily on that day, just not with significant numbers of American medium tanks, nor did he inflict significant casualties, nor did he fight a "lone battle" against "incredible" odds (except that he did fight with his back to the wall, as did all those trapped by the American advance, who most certainly were collectively badly outnumbered in an operational sense.
http://forum.axishistory.com/viewtopic.php?f=54&t=156158
Which all means that one of the most famous tank battles in Normandy may well not have been as advertised. They seldom are when medals are issued.
Good Hunting.
MR